Brushes generally used for applying mascara to the eyelashes are made up of bristles disposed on a core or support made of twisted iron wire. The bristles are fixed radially on this same core in such a way as to form rings, or more frequently a helix. The outer envelope defined by the end of the bristles may have a cylindrical, cylindroconical or conical shape. The twisted iron wire is generally fixed in a sleeve that makes it possible to manipulate the brush.
Mascara brushes are meant to be used for makeup having the following three characteristics: It separates the eyelashes well, so that they do not stick together in clumps; it is homogeneous; and only a minimum number of passes of the brush is needed. For good separation of the eyelashes and to prevent them from sticking together, the bristles of the brush must be able to pass between two eyelashes, separating them; in other words, the brush combs the eyelashes. If the makeup is to be homogenous, the brush must be able to coat the eyelash with mascara over its entire length, and with a constant quantity of mascara.
In British Patent Application BG A 2 170 996, a brush that includes long bristles and short bristles has been proposed. The long bristles form naps disposed in longitudinal rows or in the form of a helix; the width of the nap of long bristles is not insignificant and is too large to enable good separation of adjacent eyelashes.
In French Patent Application FR A 2 605 505, the applicant has proposed a brush including long bristles and shorter bristles in which the thickness of the crests, measured at the periphery of the brush, equals at most 1.5 mm. Particularly in a plane perpendicular to the core, the ends of the bristles form an envelope comprising a polygon having from three to six sides, which are rectilinear or concave. These brushes improve combing of the eyelashes, and each of the apexes of the polygon, which is made up of tufts of approximately 2 to 4 long bristles, acts as a comb.
The successive apexes are separated by an interval equal to the distance between two rings of bristles, or to the pitch of the helix, and they are aligned longitudinally in such a manner as to form a crest. Hence the crest forms a rectilinear "comb". The eyelashes enter between the teeth of the "comb" and are separated, while sweeping the makeup product located on the shorter bristles into the zone connecting the crests. Both good separation and good coating of the eyelashes are obtained.